Effects of carbon dioxide/bicarbonate on induction of DNA single‐strand breaks and formation of 8‐nitroguanine, 8‐oxoguanine and base‐propenal mediated by peroxynitrite

[摘要]

Carbon dioxide has been reported to react with peroxynitrite (ONOO⁻), a strong oxidant and nitrating agent, to form an ONO₂CO₂ ⁻ adduct, altering the reactivity characteristic of peroxynitrite. We found that bicarbonate (0–10 mM) caused a dose-dependent increase of up to 6-fold in the formation of 8-nitroguanine in calf-thymus DNA incubated with 0.1 mM peroxynitrite, whereas it produced no apparent effect on 8-oxoguanine formation. In contrast, bicarbonate inhibited peroxynitrite-induced strand breakage in plasmid pBR322 DNA and thymine-propenal formation from thymidine. We conclude that reacts with peroxynitrite to form a potent nitrating agent, but also to inactivate hydroxyl-radical-like activity of peroxynitrous acid.

[学科分类] 生物化学/生物物理

[关键词] Carbon dioxide;Peroxynitrite;8-Nitroguanine;8-Oxoguanine;DNA strand break;Thymine-propenal;nitro8Gua;8-nitroguanine;oxo8Gua;8-oxoguanine;amino8Gua;8-aminoguanine;EC;electrochemical detector;DTPA;diethylenetriaminepentaacetic acid;DMSO;dimethylsulfoxide